Screw-propeller.



N0. 680,67l. Patented Aug. l3, I90l. F. W. BREWSTER.

SCREW PBOPELLER.

(Application flled may 2, 1901.)

4 Sheets-Sheet I.

(No Model.)

-.. i UM Blumfim.

A WQQ:

In: uonms PETERS co. Puo'ro-\.|mo., wasmuurou. o. c.

N0. 680,67l. Patented Aug. l3, I901. F. W. BREWSTER. SCREW PROPELLE'B.

(Application filed May 2, 1901 V 4 Sheets-Sheet 2.

(No Model.)

"In: Nonms PETERS ca. PMoTo-umm. wxsumcmu, n. c.

No. 680,67l. Patented Aug; I3, l90l.

F. W. BREWSTER.

SGBEW PBOPELLER.

(Application filed May 2, 1901.) (No Model.)

4 Sheets$h eet 3.

"m: mums vnzns co, FNDTO-LITHO.. WASHINGTON, n. c.

(No Model.)

.Patented Aug. 13, mm. F. W. BREWSTER.

SCREW PROPELLEB.

(Application filed May-2. 190x.)

4 Sheets-Shoat 4,

n1: NORRIS wrrzns :0 PHoTo-urnu, WASHINGTON, u. c.

NrTED STATES FRANCIS \VENTWORTH BREWSTER, OF LONDON, ENGLAND, ASSIGNOR TO THE MYERS SCRE\V PROPELLER SYNDICATE, LIMITED, OF MANCHESTER, ENGLAND.

SCREW-PROPELLER.

SPECIFICATION formingpart of Letters Patent NO. 680,671, dated August 13, 1901. Application filed May 2, 1901. Serial No. 58,446. (No model.)

T all whom it may concern: vance (speaking relatively to the longitudi- Be it known that I, FRANCIS WENTWORTH nal direction of the propeller-shaft and di- BREWSTER, a subject of the King of Great rection of movement of the vessel) of that of Britain and Ireland, and a resident of Lonthe following limb of the loop, so that such 5 don, England,have invented certain new and loop root ends will rotate and pass through useful Improvements in Screw Propellers, the water in parallel planes and no part of the (for which I have filed an application for Britfollowing loop-limb will be masked or blanish patent, No. 17,625, dated October 4, 1900;) keted by any part of the leading loop-limb and I do hereby declare the following to be a and so that there will be a clear and unobto full, clear, and exact description of the same. structed waterway between such respective This invention relates to screw-propellers limbs in the plane of rotation of the propeller for ships or vessels, and has special reference andthrough which the water caused to pass to that class of such propellers which has between the loop-limbs by the revolution of blades in the form of severed loops attached the propeller will pass between the aft side of r 5 at each root end to the propeller-boss or to a the leading limb and the fore side of the folbase adapted to be attached to such boss, the lowing limb, whereby the whole propelling object of the invention being to improve the area of both limbs of the loop-formed blade efficiency of action of such propellers. In will be caused to operate against the normal such screw-propellers as hitherto made the resistance of the water and the full efficiency 2o root ends of each loop formed blade have of action and the full advantages due to been so placed and arranged relatively to each screw-propellers of such formation will be obother that the root end of the leading limb of tained. the loop has been set directly in front of The invention is represented on the accom- (speaking relatively to the direction of rotapanying drawings in Figures 1 to 4:, 5 to 8, 9, 7 5 2 5 tion of the propeller) and caused to rotate and and 10, which represent difierently shaped pass through the water in the same plane as propellers of the class aforesaid made in acthat of the root end of the following limb of cordance with the present improvements the loop, so that the water caused to pass be- Fig. 1 represents an end on or axial view of tween the loop-limbs by therevolution of the the improved propeller-blade, the arrow- 3o propeller passes between the fore side of the headed line A representing the axis of the leading limb and the aft side of the followpropeller-shaft and the direction of moveing limb. This formation and arrangement ment of the vessel forward. Fig. 2 represents of the severed loop-formed blade is disadvana side elevation of Fig. 1 looking in the directageous and reduces the effective propelling tion of the plane of rotation indicated by the 35 area of the latter, as the loop-limbs tend to arrow B. 3 represents a rear elevation carry around the water passing between them, of Fig. 2 looking forward in the longitudinal and consequently to lessen its resistance, in direction of the propeller-shaft. Fig. 4: repconsequence whereof the full efficiency of acresents a plan of Fig. 3'in section on the line tion and the full advantages due to screwas. Figs. 5, 6, 7, and Srepresent correspondo 40 propellers of such formation have not hithing views to Figs. 1, 2, 3, and 4, respectively, erto been obtained. The present improvebut of a propeller of adifierent-shape, Fig. 8 ments are designed to remedy such disadvanshowing a section on the line 8 8, Fig. 7. Fig. tages and to enable the full efficiency of ac- 9 represents a view in the plane of rotation, tion due to each limb of the severed loop and Fig. 10 represents aview in the direction 5 45 formed propeller-blade to be obtained; and of the propeller-shaft,ofapropeller of another to this end the invention is characterized by shape. so forming the respective limbs of the sev- (t represents the root end portion of the cred loop-formed blade that the root ends of leading limb, a of the severed loop-formed such limbs are arranged in helical continuity, propeller-blade, and 1) represents the root end 50 that of the leading limb of the loop being set portion of the following limb'b' of the blade, and connected to the propeller-boss in adcbeing the circumferential part of the blade.

It will be seen on reference to the drawings, particularly to Figs. 1, 2, 4 to 6, 8, and 9, that the blade-loop root end portions ab are set in helicalcontinuity, thatof the leading limb a, being set and connected to the propeller-boss in advance (speaking relatively to the longitudinal direction of the propeller-shaft A) of that of the following limb b in such manner that such loop end parts a b will rotate and pass through the water in different planes, that of the former in-advance of that of the latter, so that no part of the following limb b will be masked or blanketed in the plane of rotation by any part of the leading limb a and so that there will be a clear and unobstructed waterway between such respective limbs in the plane of rotation of the propeller, whereby the whole propelling area of the severed loop-formed blade will be caused to operate against the resistance of the water and the full efficiency of action of the propeller will be obtained.

The improved severed loop-formed blade may be set with its radial axis in perpendicular or rectangular relation to the axis of the propeller-shaft, as represented,or it may rake forward or aft to any required extent.

What I claim as my invention, and desire to secure by Letters Patent, is-

In screw-propellers for navigable vessels, a propeller-blade made in the form of a severed loop having its leading-and following looplimbs set and attached to the propeller-boss in helical continuity, the leading limb being set and connected to the boss in advance,relatively to the line of the propeller-shaft,of the following limb so that such loop-limbs will rotate and pass through the water in parallel planes without the one blanketing the other, as set forth.

In testimony whereof I have signed this specification in the presence of two subscribing witnesses.

FRANCIS WENTWORTH BREWSTER.

W'itnesses:

HAROLD Wmrcuuscn lllOORING ALDRIDGE, JOHN ROBERT Ilium-0RD. 

